Natural and anthropogenic consequences of tropical forest soils in Northern Peru using environmental radionuclides as radiotracers

Environmental radionuclides (⁴⁰K, ¹³⁷Cs, ²¹⁰Pb, ²²⁶Ra) were determined in soils under semi-arid stands, a transition area from thorn to deciduous forest in El Angolo, and heath stands in the Alto Mayo in Northern Peru in order to elucidate their activity level in soil, and to trace underground environment in remote areas of little anthropogenic intervention. Anthropogenic ¹³⁷Cs was only found in the uppermost portion of the soils in small amount, whereas the ²¹⁰Pb activity was exceptionally high at the soil surfaces in a tropical stand of Alto Mayo. The results suggest a fallout nuclide, ²¹⁰Pb, having been transported from local source(s) not to be specified yet. (author)